Patent GB-855884-A (GB)
Title: Intermittent weighing and weight indicating apparatus
Inventor: BROWN SIDNEY CHARLES
IPC: G01G23/26
Filed: 1957-07-23
Abstract: 855,884. Weighing apparatus. ADEQUATE WEIGHERS Ltd. July 17, 1958 [July 23, 1957], No. 23356/57. Class 143 An apparatus for weighing an intermittent succession of loads comprises a frame 8, and a pendulum 31 movable in accordance with a load 125 on the apparatus to vary accordingly an infinitely variable change speed gear 39, 40, 41 which is driven by a constant speed shaft 42 and the output shaft 431 of which drives the pointer of an indicator 53, there-being control means actuated by movement of the load 125 relative to the frame 8 which effects locking of the pendulum 31 in its moved position and clutching and unclutching of the indicator driving shaft 43 all in a fixed predetermined timed succession so that once triggered, the indicator will be driven to register an indication of the load weight even though the load may have passed over and beyond the weighing apparatus. As shown a horizontal weigh rail 1 is inserted in conveyer rail 2 and is suspended from knife edges 4 on a pair of levers 5 which are in turn suspended at one end from the frame 8 and bear at their other ends 9 on a frame-suspended lever 12. The lever 12 has a pull rod 17 pivoted at its remote end to depend into a casing 18, Fig. 6, carried by the frame 8, the rod 17 transmitting its motion through a centrally pivoted lever 21 to a rod 28 which pulls on an arm 30 of the pendulum 31, Fig. 4. The pendulum 31 has an arm 311 with a slidable zeroing weight 3111 thereon, and an arm 34 pivotally connected at 35 to its lower end, the upper end of the arm 34 comprising a fork 36 embracing a hardened steel ball 39. A link 37 ensures parallel horizontal motion of the fork on swing of the pendulum. The ball 39 transmits drive from a cylindrical roller 40, Fig. 5, on the constant speed shaft 42 of a gearbox 43, to a conical roller 41 on the driven shaft 431, the ball 39 being held in engagement between the rollers by a magnet 44. Movement of the ball on swing of the pendulum varies the speed of the shaft 431 which, through a differential 441, gears 47-48<SP>1</SP>, and a clutch 49, drives the shaft 50 of the indicator pointer 52. The clutch 49 comprises an armature plate 54, Fig. 11, on the end of the indicator shaft 50 disposed between a fixed electro-magnet 59, and an electro-magnet 56 on the shaft 55 of the gear 481, the selective energisation of the magnets 56, 59 to drive or brake the indicator being controlled by a switch 79, Fig. 9, operable by a rocker shaft 77 of the control means. The control means comprises a plate 64 driven continuously at constant speed from a gearbox output shaft 62, Fig. 7, which may be the shaft 42, and pressed by springs 65 into frictional engagement with a rotary cam assembly 70, 68, 66. The cam 70 has a stop 73 engaging a latch lever 74 which holds the assembly against rotation by the plate 64 and is electrically operable to release the assembly by a limit switch 119 actuated by a skip 125 in its passage along the weigh rail 1. The cam 70 also has a peripheral notch 71 and a facial rise 72, and the cams 66, 68 each have a rise 67, 69 respectively co-operating with a roller-ended arm 85, 86 of a lever freely mounted on the rocker shaft 77. A third arm 89 of the lever Fig. 10, is disposed between springs 91, 92 carried between arms 93, 94 of a member 95 fixed to the shaft 77, the lower ends 96, 97 of the arms 93, 94 bearing on the periphery of the cam 70. Associated with the control means is the pendulum locking means which comprises a scissors lever assembly 99, 100, Fig. 7, spring loaded to grip a plate 98 Figs. 4 and 7, carried by the pendulum 31. The scissors lever is operable to free the pendulum by a pointed rod 108 movable between rollers 106, 107 at the ends of the scissors lever remote from the plate 98, the rod 108 being spring loaded to move to expand the scissors and being normally latched out of operation by a lever 116 engaging a collar 115 on the rod. A resetting lever 112. Fig. 10 operable by the rise 72 on the cam 70 co-operates with a collar 110 on the rod 108 to move the rod back into latched position. In operation, as a skip 125 carried by a bogie 126 moves on to the weigh rail 1, a limit switch 118 is actuated to energise momentarily a solenoid (not shown) which rocks the lever 116 to unlatch the rod 108 and allow it to expand the scissors lever 99, 100 and free the pendulum. The pendulum then swings to a position corresponding to the weight of the skip and at the same time moves the ball 39 accordingly to set the speed of the shafts 43<SP>1</SP> and 50. The skip continues its travel along the rail 1 and then operates the switch 119 which energises momentarily a second solenoid (not shown) which rocks the level 74 out of the path of the stop 73 and allows rotation of the control cam assembly. The rise 72 on the cam 70 then rocks the lever 112 to withdraw the rod 108 thereby locking the pendulum plate 98 and allowing the latch lever 116 to engage the rod collar 115 and hold the rod in its retracted position. The rise 69 on cam 68 then rocks the lever arm 86 to compress the spring 91 and cause the end 96 of the member 95 to bear on the periphery of cam 70 and eventually drop into the notch 71, thereby rocking the shaft 77 to actuate the switch 79 and energise the magnet 56, the brake magnet 59 being simultaneously de-energised. The clutch plate 54 is engaged with the shaft 55 to drive the shaft 50 and thereby the pointer 52. The drive continues for a fixed time equal to about 330 degrees of revolution of the constant speed rotary cam, to give an ultimate indication of the skip weight. At the end of its rotation, the rise 67 on the cam 66 rocks the lever arm 85 and thereby the shaft 77 to de-energise the clutch magnet 56 and energise the brake magnet 59 and arrest the pointer of the indicator. Finally the stop 73 on the cam 70 abuts the lever 74 and stops rotation of the control cam assembly. The Provisional Specification states that the magnetic clutch and brake in the recorder drive may be replaced by a spring toggle-lever arrangement, and reference is made therein to Specification 587,756.